Typical vapor sensor devices, such as those that are used to determine O2 gas levels and breathalyzer units for alcohol measurement rely on complex chemical processes that make the devices costly. For example, breathalyzer units rely on chemical reactions, infrared radiation analysis, or fuel cells to measure blood alcohol content. Such devices are relatively complex, and can be expensive. There exists a need for a low-cost simple alternative sensing unit for the detection of various solvent vapors.